The phenomenon that the free market is getting away from America. Trump is a nationalist and Trump imitates China's strategy when protecting private Chinese from the onslaught of foreign platforms. Where China created and raised the Chinese version of the platform, including; Alibaba is China's Amazon, Wechat is China's WA, QQ is China's Gmail, Weibo is China's Twitter, Renren is China's FB, and apps like Baidu, Didi Chuxing, Baike, Nice and Youku. With the protection of the private state, China does not need to compete with foreign products, which in the end, even though they belong to the nationality, are owned by foreigners (happened in my country)
Trump as a nationalist sees that a large number of active users of Tik Tok around the world with a large capitalization is a national threat for America because it is global. Trump is trying to control globalists through pressure to divest and create similar applications. Will this Trump strategy reverse the habit of "oligarchs controlling government officials", becoming a state controlling oligarchs. National Threat is the reason that allows Trump to control Facebook, Instagram, Twitter and Tik Tok.
The world has been shifting to globalism for some decades now, it's unlikely that one person in power can reverse course at this point. Think for a second if Facebook, Twitter, Amazon etc. could only get traffic from US users because of a nationalist policy. This hurts the company, and all the consumers elsewhere that could've benefited from the service. Also, if Honda, Toyota et al could only sell their cars to Japanese customers, then demand will decrease and cause a drop in markets and eventually make a depression.